The diode used in the circuit shown in the figure has a constant voltage drop of $0.5 \, V$ at all currents and a maximum power rating of $100 \, mW$. What should be the value of the resistor $R$,connected in series with the diode,to obtain the maximum current?

In a two-slit experiment with monochromatic light,fringes are obtained on a screen placed at some distance from the slits. If the screen is moved by $5 \times 10^{-2} \ m$ towards the slits,the change in fringe width is $3 \times 10^{-5} \ m$. If the separation between the slits is $10^{-3} \ m$,the wavelength of light used is ......... $\mathring{A}$.

When a wave traverses a medium,the displacement of a particle located at $x$ at a time $t$ is given by $y = a \sin (bt - cx)$,where $a, b,$ and $c$ are constants of the wave. Which of the following is a quantity with dimensions?

The pattern of standing waves formed on a stretched string at two instants of time (extreme and mean positions) is shown in the figure. The velocity of the two waves superimposing to form stationary waves is $360 \ m/s$ and their frequency is $256 \ Hz$. Which of the following is not a possible value of $t$ (in $sec$)?

Which of the following is the correct order of acidic strength?

........ of a reaction cannot be determined experimentally.